The purpose of the study is to address the issue of how alterations in arterial stiffness that occur with adult aging affect the myocardium. The interaction of age, arterial pressure, and vascular stiffness on myocardial structure and function shall be addressed by simultaneous measurements of those parameters in a population that is genetically homogeneous but is comprised of individuals in a broad age range who exhibit a spectrum of arterial stiffness. The study population shall consist of a minimum of 800 individuals of each sex evenly distributed across the age range of 20 to 90-100 years who are free of clinical diseases (except hypertension) that can affect arterial or cardiac properties.